832 



THE DOMESTIC SHEEP. 



we may see deposited in clusters on meat, much to the disgust 

 of the annoyed housewife. The author ^has spent some hours 

 in watching this habit of the fly, using a hampered sheep as the 

 subject, and has collected several specimens of the maggot. The 

 maggot very soon begins to move in a wriggling manner, drawing 



FIG. 18 (a). 



FIG. 19 (6). 



FIG. 20 (c). 



Fig. 18. Adult Female Gad- Fly slightly enlarged. 

 Fig. 19. Full-grown Grub natural size. 



Fig. 20. Head of full-grown Grub highly magnified showing hooks 

 by which the Grub attaches itself to the mucous membrane. 



itself into the nostril and disappearing in the nasal passage. In 

 one day nearly all spent in observing this single sheep eighteen 

 of these larva were deposited on its nostrils, and it appeared 

 that but one fly was engaged in the business that day. The 

 rest of thv flock had hidden near a fallen tree in the pasture, 

 thrusting their noses close to the space between the tree and the 

 soil, or were lying in fence corners with their noses under the 

 lowest rail, or huddled together with their noses buried in each 

 other's fleeces. This is the method by which the fly deposits 

 its living eggs, or newly born living young, upon its host, the un- 

 happy sheep. The fly is shown al, fig. 18 (a); its larva fully 

 grown at (b), the hooks by which the grub draws itself up the 

 nostril and attaches itself to the membrane lining the cavity of 

 the skull are shown at (c), and at fig. 21 is shown the part of the 

 skull in which the grub passes fully three-fourths of the year, 

 emerging when fully grown and falling to the ground into which 

 it burrows a little space, and remains until the warm weather, 

 when it begins active business in reproducing its race. Doubtless 

 the greater number of these grubs peinsh in the interval between 

 emerging from the sheep and completing the final transformation 

 into the fly, falling a prey to moles, birds, and carnivorous 

 beetles; but sufficient number escape to continue the race and 

 make the sheep's summer life, otherwise happy, a miserable one. 

 The parasite seems to do little real harm to the sheep except 

 to torment it, unless they are quite numerous, when the irritation 

 seems to cause so much restlessness that the sheep do not thrive, 

 but remain poor. The effect of numbers of the grubs is to inflame 

 the membrane, to cause much irritation, and at times to cause 



